Material for a molded resin for use in a semiconductor light-emitting device

ABSTRACT

The present invention provides a material for a molded resin as a material for a semiconductor light-emitting device that can yield a highly durable (light resistance and heat resistance) molded resin and can also improve the LED output through an excellent reflectivity. The present invention also provides an easily moldable material for a molded resin for a semiconductor light-emitting device. The material for a molded resin for a semiconductor light-emitting device is a resin composition comprising (A) a polyorganosiloxane, (B) a white pigment, and (C) a curing catalyst, wherein the white pigment (B) has the following characteristics (a) and (b); (a) an aspect ratio 1.2 or more and 4.0 or less, and (b) a primary particle diameter 0.1 μm or more and 2.0 μm or less.

TECHNICAL FIELD

The present invention relates to a material for a molded resin that isused in a semiconductor light-emitting device that has a light-emittingelement, for example, a light-emitting diode, and to a molding made ofthe material.

BACKGROUND ART

As shown in FIG. 1, a semiconductor light-emitting device made, bymounting a semiconductor light-emitting element is composed of, forexample, a semiconductor light-emitting element 1, a molded resin 2, abonding wire 3, an encapsulant 4, and a lead frame 5. The structurecomprising the electroconductive metal interconnects, e.g., the leadframe, and the insulating molded resin is referred to as the package.

Insulating materials provided by incorporating a white pigment in athermoplastic resin, e.g., a polyamide, have already entered intogeneral use as insulating materials used for molded resins (refer, forexample, to Patent Document 1). In the case of semiconductorlight-emitting devices where directionality is required of the emittedlight, the light-emitting efficiency is raised not just by the lightemitted in the desired direction from the semiconductor light-emittingelement, but also by causing light emitted in undesired directions to bereflected from, e.g., the molded resin, metal interconnects such as thelead frame, and reflectors, into the desired direction. Sincethermoplastic resins such as polyamides are light permeable, thelight-emitting efficiency of a semiconductor light-emitting device canbe raised by incorporating—when light is to be reflected by the moldedresin—a white pigment in the resin and reflecting the light emitted fromthe semiconductor light-emitting element by utilizing the difference inthe refractive indices between the resin and white pigment.

Even when a white pigment is used in Patent Document 1, its reflectionefficiency may not be satisfactory depending on the particular type ofwhite pigment, and light absorbed in the molded resin and lightpenetrating through the molded resin also ultimately escape. Due tothis, it has not been possible in some cases to concentrate the lightfrom the semiconductor light-emitting element in the desired directionand the light-emitting efficiency of the semiconductor light-emittingdevice has been reduced as a result.

In addition, there is currently a trend toward higher reflowtemperatures due to a strong trend toward the use of higher meltinglead-free solders brought on by environmental concerns. Polyamides arethermoplastic resins, and polyamides are thus softened by this heat andthe heat resistance of the package then becomes a problem in the case ofpackages that use polyamide. Furthermore, polyamides are subject tophotodegradation and thermal degradation by ultraviolet radiation andheat, and degradation by light has become a problem in particular whenlight-emitting elements are used that have a light-emission range thatextends into high-energy wavelength regions, such as the blue tonear-ultraviolet semiconductor light-emitting elements whosecommercialization has been ongoing in the recent years. Moreover,thermal degradation and photodegradation have become even moresignificant problems due to the heat and high luminous flux lightgenerated by the semiconductor light-emitting element as a result ofcontemporary demands for brighter light-emitting elements.

Otherwise, an alumina-containing sintered ceramic may be used as theinsulating material in those cases in which heat resistance is required(refer, for example, to Patent Document 2). A package that uses thisceramic does have a good heat resistance, but its production requires ahigh-temperature sintering step post-molding. This sintering step hasposed the following problems: cost problems due, for example, toelectricity costs; the ease of appearance of defective products due tochanges in the size and shape of the molding caused by sintering; and animpaired productivity.

In contrast to the preceding, a case has also recently been introducedthat is provided by molding a silicone resin composition that uses anorganopolysiloxane for the resin and uses titanium oxide for the whitepigment (refer, for example, to Patent Document 3). The use of theorganopolysiloxane for the resin is intended to improve the heatresistance over that for the use of polyamide.

Patent Document 1: Japanese Patent Application Laid-open No. 2002-283498

Patent Document 2: Japanese Patent Application Laid-open No. 2004-288937

Patent Document 3: Japanese Patent Application Laid-open No. 2009-155415

SUMMARY OF INVENTION Technical Problem

The following problems are produced by the use of titanium oxide for thewhite pigment in the case of Patent Document 3, which teaches the use ofpolyorganosiloxane for the resin.

First, titanium oxide has a low dispersibility in the resin when, duringthe step of preparing the resin composition, titanium oxide is added toand mixed into the polyorganosiloxane used for the resin. As aconsequence, the titanium oxide is not uniformly dispersed in the moldedresin provided by the cure of the resin composition and the reflectivitywithin the molded resin is then not constant, which results in problemswith the uniformity of the light emitted from the semiconductorlight-emitting device.

In addition, since titanium oxide is photocatalytic, when asemiconductor light-emitting element having a wavelength at or belowabout 470 nm is used, the molded resin in proximity to a titanium oxideparticle is degraded by the light emitted by the semiconductorlight-emitting element and by the light generated by phosphors excitedby the light emitted by the semiconductor light-emitting element. As aconsequence, the light resistance of the molded resin is seriouslyimpaired when a semiconductor light-emitting element is used that emitslight in the blue region and when a semiconductor light-emitting elementis used that emits light in the near-ultraviolet region.

Furthermore, titanium oxide has an absorption wavelength in thenear-ultraviolet region and as a result its color assumes a yellowishtinge. Due to this, the spectrum of the light emitted from thesemiconductor light-emitting element is altered, producing a problemwith the whiteness and the color rendering property of the light emittedby the semiconductor light-emitting device. The whiteness and the colorrendering property in particular are major requirements for the whitesemiconductor light-emitting devices that are currently the subject ofactive research, and titanium oxide is also unfavorable from thisperspective.

A problem for the present invention is to provide a material for amolded resin wherein the material can yield a highly durable (lightresistance and heat resistance) molded resin for a semiconductorlight-emitting device and can also improve the LED output through anexcellent reflectivity. Another problem for the present invention is toprovide an easily moldable material for a molded resin for asemiconductor light-emitting device.

Solution to Problem

As a result of intensive investigations in order to achieve the objectsindicated above, the present inventors discovered that the problemsindicated above could be solved by the use of a white pigment that hasspecific shape characteristics in the material—wherein this materialcomprises a polyorganosiloxane, a white pigment, and a curingcatalyst—for the molded resin for a semiconductor light-emitting device.

Thus, the present invention is as follows,

(1) A material for a molded resin for a semiconductor light-emittingdevice, the material comprising (A) a polyorganosiloxane, (B) a whitepigment, and (C) a curing catalyst, wherein the white pigment (B) hasthe following characteristics (a) and (b):

(a) a primary particle aspect ratio is 1.2 or more and 4.0 or less, and

(b) a primary particle diameter is 0.1 μm or more and 2.0 μm or less.

(2) The material for a molded resin according to (1), wherein a mediandiameter of secondary particles of the white pigment (B) is 0.2 μm ormore and 5 μm or less.

(3) The material for a molded resin according to (1) or (2), wherein aviscosity at a shear rate of 100 s⁻¹ and at 25° C. is 10 Pa·s or moreand 10,000 Pa·s or less.

(4) The material for a molded resin according to (3), wherein a radio ofa viscosity at a shear rate of 1 s⁻¹ to a viscosity at a shear rate of100 s⁻¹ of is least 15.

(5) The material for a molded resin according to any of (1) to (4),wherein the white pigment (B) is alumina.

(6) The material for a molded resin according to any of (1) to (5),wherein the ratio y/x of the median diameter y of the secondaryparticles in the white pigment (B) to the primary particle diameter x inthe white pigment (B) is 1 or more and 10 or less.

(7) The material for a molded resin according to any of (1) to (6),wherein the polyorganosiloxane (A) is a thermosetting polyorganosiloxanethat is a liquid at normal temperature and normal pressure.

(8) The material for, a molded resin according to any of (1) to (7)further containing (D) a cure rate controlling agent.

(9) The material for a molded resin according to any of (1) to (8)further containing (E) a fluidity controlling agent.

(10) The material for a molded resin according to (9), wherein a totalcontent of the white pigment (B) and the fluidity controlling agent (E)is at least 50 weight % with regard to the entire material for a moldedresin.

(11) A molded resin for a semiconductor light-emitting device, that isobtained by molding the material for a molded resin according to any of(1) to (10).

(12) The molded resin according to (11), wherein a light reflectivity ata thickness of 0.4 mm and a wavelength of 400 nm is at least 60%.

(13) The molded resin according to (11) or (12), wherein the moldedresin is molded by liquid injection molding.

(14) A method of producing a molded resin, comprising:

a step of producing the material for a molded resin according to any of(1) to (10); and

a step of molding the obtained material for a molded resin by injectionmolding.

(15) A semiconductor light-emitting device that has the molded resinaccording to any of (11) to (13).

(16) A material for a molded resin for a semiconductor light-emittingdevice, the material comprising (A) a polyorganosiloxane, (B) a whitepigment, and (C) a curing catalyst, wherein

a viscosity at a shear rate of 100 s⁻¹ and at 25° C. is 10 Pa·s or moreand 10,000 Pa·s or less, and a ratio of a viscosity at a shear rate of 1s⁻¹ to a viscosity at a shear rate of 100 s⁻¹ is at least 15.

Advantageous Effects of Invention

A highly durable (strongly light resistant and heat resistant) moldedresin for a semiconductor light-emitting device, that also brings aboutan improved LED output through its excellent reflectivity, can beobtained using the material of the present invention for a molded resin.Moreover, the present invention provides an easy-to-mold material for amolded resin for a semiconductor light-emitting device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional diagram that schematically depicts thestructure of one mode of a semiconductor light-emitting device;

FIG. 2 is a cross-sectional diagram that schematically depicts thestructure of another mode of a semiconductor light-emitting device;

FIG. 3 is a cross-sectional diagram that schematically depicts one modeof a semiconductor light-emitting device that is provided with aconventional package;

FIG. 4 is a graph that shows the results of reflectivity measurements onthe test pieces of Examples 1 to 7 and Comparative Examples 1 to 6;

FIG. 5 is a graph that shows the results of reflectivity measurements onthe test pieces of Examples 8 and 9 and Comparative Example 7; and

FIG. 6 is a graph that shows the results of viscosity measurements onthe molded resin materials of Examples 1 to 7 and Comparative Examples2, 4, and 5.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention are described in detail herebelow,but the present invention is not limited to the following embodimentsand can be carried out using various modifications within the scope ofits essential features.

<1. The Material for a Molded Resin for a Semiconductor Light-EmittingDevice>

The material of the present invention for a molded resin for asemiconductor light-emitting device is a material that is used to mold amolded resin for a semiconductor light-emitting device. It specificallycontains (A) a polyorganosiloxane, (B) a white pigment, and (C) a curingcatalyst.

Here, the molded resin for a semiconductor light-emitting device is amolding provided by the cure of the material and forms a package for asemiconductor light-emitting device by molding with an electroconductivemetal interconnect such as a lead frame. The semiconductorlight-emitting device is a light-emitting device that contains asemiconductor light-emitting element in the aforementioned molded resinfor a semiconductor light-emitting device. A schematic diagram of thecross section of a semiconductor light-emitting device is shown in FIG.1.

<1-1. The Polyorganosiloxane (A)>

The polyorganosiloxane in the present invention denotes a polymericsubstance in which an organic group is added onto a structure that has amoiety in which a silicon atom is bonded across oxygen to anothersilicon atom. This polyorganosiloxane is preferably a liquid at normaltemperature and normal pressure. This facilitates handling of thematerial during molding of the molded resin for a semiconductorlight-emitting device. In addition, a polyorganosiloxane that is solidat normal temperature and normal pressure, while generally having arelatively high hardness in the form of the cured material, tends tooften have a low toughness due to the low energy required for ruptureand to have an inadequate light resistance and heat resistance and thusbe susceptible to discoloration by light or heat.

The normal temperature referenced above denotes a temperature in therange of 20° C.±15° C. (5 to 35° C.), and the normal pressure denotes apressure equal to atmospheric pressure and is approximately oneatmosphere, in addition, liquid denotes a state that exhibits fluidity.

The aforementioned polyorganosiloxane generally denotes an organicpolymer in which the siloxane bond makes up the main chain and can beexemplified by a compound represented by the following compositionalformula (1) and by mixtures thereof.

(R¹R²R³SiO_(1/2))_(M)(R⁴R⁵SiO_(2/2))_(D)(R⁶SiO_(3/2))_(T)(SiO_(4/2))_(Q)  (1)

R¹ to R⁶ in formula (1) are each independently selected from organicfunctional groups, the hydroxyl group, and the hydrogen atom. M, D, T,and Q are greater than or equal to 0 but less than 1 and are numbersthat satisfy M+D+T+Q=1.

The main units making up the polyorganosiloxane are the monofunctionalunit [R₃SiO_(0.5)] (triorganosilhemioxane), difunctional unit [R₂SiO](diorganosiloxane), trifunctional unit [RSiO_(1.5)](organosiisesquioxane), and tetrafunctional unit [SiO₂] (silicate). Theproperties of the polyorganosiloxane can be changed by altering theconstituent proportions of these four units, and the polyorganosiloxaneis synthesized using a suitable selection therefrom so as to obtain thedesired characteristics.

A polyorganosiloxane in which the constituent units are mono- totrifunctional units can be synthesized based on the series oforganosilicon compounds known as organochlorosilanes (general formula:R_(n)SiCl_(4-n) (n=1 to 3)). For example, methylchlorosilane can besynthesized, for example, by the direct reaction of silicon Si andmethyl chloride at high temperatures in the presence of a Cu catalyst,and silanes having an organic group, e.g., the vinyl group, can besynthesized by standard methods in organic synthetic chemistry.

A silanol is produced when the isolated organochlorosilane, either asthe individual organochlorosilane or as a mixture of organochlorosilanesin any proportion, is hydrolyzed with water, and the polyorganosiloxane,which is the basic skeleton of a silicone, is synthesized by thedehydration synthesis of the silanol.

The polyorganosiloxane can be cured in the presence of a curing catalystby the application of, for example, thermal energy or light energy. Thiscuring refers to a change from a state that exhibits fluidity to a statethat docs not exhibit fluidity. For example, the uncured state refers toa state in which fluidity is present when a specimen is held for 30minutes while inclined 45° from the horizontal, while a state in whichfluidity is entirely absent can be assessed as the cured state.

Polyorganosiloxanes can generally be classified by curing mechanism intoaddition polymerization curing type polyorganosiloxanes,polycondensation curing type polyorganosiloxanes, ultraviolet curingtype polyorganosiloxanes, and peroxide vulcanization typepolyorganosiloxanes. Among these types, the addition polymerizationcuring types (addition-type polyorganosiloxanes) and condensation curingtypes (condensation-type polyorganosiloxanes) are favorable. Withinthese types, polyorganosiloxanes that cure by hydrosilylation (additionpolymerization), which does not produce by-products and is not areversible reaction, are more favorable. The reason for this is thatwhen by-products are produced during the molding step, they tend toraise the pressure within the molded container and/or to remain asbubbles within the cured material.

Addition-type polyorganosiloxanes and condensation-typepolyorganosiloxanes are described in greater detail in the following.

<1-1-1. Addition-Type Polyorganosiloxanes>

Addition-type polyorganosiloxanes refer to polyorganosiloxanes in whichthe polyorganosiloxane chain is crosslinked by an organic addition bond.In a typical case, for example, (C1) a silicon-containing compoundhaving an alkenyl group, e.g., a vinylsilane, is mixed with, forexample, (C2) a silicon compound having the hydrosilyl group, e.g., ahydrosilane, at a quantitative ratio that provides a total amount ofhydrosilyl group that as 0.5-fold or more and 4.0-fold or less, and acompound having the Si—C—C—Si bond at its crosslink sites is obtained byreaction in the presence of (C3) an addition polymerization catalystsuch as a Pt catalyst.

The alkenyl group-bearing silicon-containing compound (C1) can beexemplified by a polyorganosiloxane represented by the following generalformula (2)

R_(n)SiO_([(4-n)/2])  (2)

and having at least two silicon atom-bonded alkenyl groups in eachmolecule.

Each R in formula (2) is independently selected from identical ordifferent substituted or unsubstituted monovalent hydrocarbon groups andalkoxy groups and the hydroxyl group, and n is a positive number thatsatisfies 1≦n<2.

The alkenyl group in the alkenyl group-bearing silicon-containingcompound (C1) is preferably a C₂₋₈ alkenyl group, for example, the vinylgroup, allyl group, butenyl group, pentenyl group, and so forth. When Ris a hydrocarbon group, it is selected from C₁₋₂₀ monovalent hydrocarbongroups, e.g., alkyl groups such as the methyl group and ethyl group, thevinyl group, the phenyl group, and so forth. The methyl group, ethylgroup, and phenyl group are preferred.

Each may be different, but when UV resistance is required, preferablyabout 65% of the R in the preceding formula is the methyl group (thatis, the number of non-methyl functional groups present with reference tothe number of Si (number of moles) is preferably not more than 0.35(mol)) and more preferably at least 80% of the R in the precedingformula is the methyl group. R may also be a C₁₋₈ alkoxy group or thehydroxyl group, but the content of the alkoxy group and hydroxyl groupis preferably not more than 10 weight % of the alkenyl group-bearingsilicon-containing compound (C1). In addition, n is a positive numberthat satisfies 1≦n<2. When this value is greater than or equal to 2, anadequate strength is not obtained for the adhesion between theconductors, e.g., the lead frame, and the material for a molded resin,while synthesis of this polyorganosiloxane becomes quite difficult whenthis value is less than 1.

The alkenyl group-bearing silicon-containing compound (C1) can be, forexample, a vinylsilane or a vinyl group-containing polyorganosiloxane,and a single one of these can be used by itself or two or more may beused in any ratio and combination. A vinyl group-containingpolyorganosiloxane having at least two vinyl groups in the molecule ispreferred among the preceding.

The following are specific examples of vinyl group-containingpolyorganosiloxanes that have at least two vinyl groups in the molecule.

Both-end vinyl-terminated polydimethylsiloxanes

DMS-V00, DMS-V03, DMS-V05, DMS-V21, DMS-V22, DMS-V25, DMS-V31, DMS-V33,DMS-V35, DMS-V41, DMS-V42, DMS-V46, and DMS-V52 (all from Gelest, Inc.)

Both-end vinyl-terminated dimethylsiloxane-diphenylsiloxane copolymers

PDV-0325, PDV-0331, PDV-0341, PDV-0346, PDV-0525, PDV-0541, PDV-1625,PDV-1631, PDV-1635, PDV-1641, PDV-2331, and PDV-2335 (all from Gelest,Inc.)

Both-end vinyl-terminated phenylmethylsiloxanes

PMV-9925 (from Gelest, Inc.)

trimethylsilyl-end-capped vinylmethylsiloxane-dimethylsiloxanecopolymers

VDT-123, VDT-127, VDT-131, VDT-153, VDT-431, VDT-731, and VDT-954 (allfrom Gelest, Inc.)

vinyl T-structure polymers

VTT-106 and MTV-124 (both from Gelest, Inc.)

The hydrosilyl group-bearing silicon-containing compound (C2) can be,for example, a hydrosilane or a hydrosilyl group-bearingpolyorganosiloxane, and a single one of these can be used by itself ortwo or more may be used in any ratio and combination. A hydrosilylgroup-bearing polyorganosiloxane that has at least two hydrosilyl groupsin the molecule is preferred here.

The following are specific examples of polyorganosiloxanes that containat least two hydrosilyl groups in the molecule.

Both-end hydrosilyl-terminated polydimethylsiloxanes

DMS-H03, DMS-H11, DMS-H21, DMS-H25, DMS-H31, and DMS-H41 (all fromGelest, Inc.)

trimethylsilyl-both-end-capped methylhydrosiloxane-dimethylsiloxanecopolymers

HMS-013, HMS-031, HMS-064, HMS-071, EMS-082, HMS-151, HMS-301, andHMS-501 (all from Gelest, Inc.)

The alkenyl group-bearing silicon compound (C1) and the hydrosilylgroup-bearing silicon compound (C2) are used in the present invention inamounts that provide generally 0.5 mol or more, preferably 0.7 mol ormore, and more preferably 0.8 mol or more, but generally 4.0 mol orless, preferably 3.0 mol or less, and even more preferably 2.0 mol orless of the hydrosilyl group-bearing silicon compound (C2) (number ofmoles of the hydrosilyl group) per 1 mole of the alkenyl group-bearingsilicon compound (C1) (number of moles of the alkenyl group).Controlling the number of moles of hydrosilyl group with reference tothe alkenyl group makes it possible to lower the post-cure amount ofunreacted terminal groups and to thereby obtain a cured material thatexhibits little timewise variation, e.g., discoloration or delamination,during use as a light source.

The content of reaction sites (crosslinking sites) where hydrosilylationoccurs is preferably 0.1 mmol/g or more and 20 mmol/g or less in theresin itself free of the white pigment for both the alkenyl group andhydrosilyl group. 0.2 mmol/g or more and 10 mmol/g or less is morepreferred.

Viewed from the standpoint of ease of handling, the viscosity of theresin prior to the addition of the white pigment is generally not morethan 100,000 cp and is preferably not more than 20,000 cp and morepreferably is not more than 10,000 cp. While there are no particularlimitations on the lower limit, it is generally at least 15 cp in viewof the relationship with the volatility (boiling point).

The weight-average molecular weight of the resin, as the averagemolecular weight value measured by gel permeation chromatography usingpolystyrene as the standard substance for the resin, is preferably 500or more and 100,000 or less. It is more preferably 700 or more and50,000 or, less. Furthermore, at least 1,000 is even more preferred forthe purpose of providing a small volatile component (in order tomaintain the adhesiveness with other articles) and not more than 25,000is also even more preferred from the standpoint of the ease of handlingof the material prior to molding. Not more than 20,000 is mostpreferred.

<1-1-2. Condensation-Type Polyorganosiloxanes>

The condensation-type polyorganosiloxanes can be exemplified bycompounds that have the Si—O—Si bond at the crosslinking sites and areobtained by the hydrolysis/polycondensation of alkylalkoxysilane.Specific examples are the polycondensates obtained by thehydrolysis/polycondensation of compounds represented by the followinggeneral formulas (3) and/or (4), and/or their oligomers.

M^(m+)X_(n)Y¹ _(m-n)  (3)

In formula (3), M represents silicon; X represents a hydrolyzable group;Y¹ represents a monovalent organic group; m represents an integergreater than or equal to 1 that represents the valence of M; and nrepresents an integer greater than or equal to 1 that represents thenumber of X groups. In addition, m≧n.

(M^(s+)X_(t)Y¹ _(s-t-1))_(u)Y²  (4)

In formula (4), M represents silicon; X represents a hydrolyzable group;Y¹ represents a monovalent organic group; Y² represents an organic groupof valence u; s represents an integer greater than or equal to 1 thatrepresents the valence of M; t represents an integer that is greaterthan or equal to 1 and less than or equal to s−1; and u represents aninteger greater than or equal to 2.

Known condensation-type polyorganosiloxanes can be used; for example,the members for semiconductor light-emitting devices described inJapanese Patent Application Laid-open Nos. 2006-77234, 2006-291018,2006-316264, 2006-336010, and 2006-348284 and WO 2006/090804 aresuitable.

<1-1-2-1. Particularly Preferred Condensation-Type Polyorganosiloxanes>

Particularly preferred materials among the condensation-typepolyorganosiloxanes are described in the following.

In the case of use in semiconductor light-emitting devices,polyorganosiloxanes generally exhibit a weak adhesiveness to, forexample, the semiconductor light-emitting elements, the substrates onwhich the semiconductor light-emitting devices are placed, the moldedresins, and so forth, and condensation-type polyorganosiloxanes thathave at least one of the following characteristics [1] and [2] arepreferred in order to provide a polyorganosiloxane that is highlyadhesive to the preceding.

[1] The silicon content is at least 20 weight %.[2] The measured solid-state Si-nuclear magnetic resonance (NMR)spectrum has at least one of the following peaks (a) and/or (b) thatoriginate with Si.

(a) Using the dimethylsiloxy silicon of dimethylsilicone rubber as thereference, a peak for which the position of the peak top is in theregion of a chemical shift −40 ppm or more and 0 ppm or less, and forwhich the peak half-width value is 0.3 ppm or more and 3.0 ppm or less.

(b) Using the dimethylsiloxy silicon of dimethylsilicone rubber as thereference, a peak for which the position of the peak top is in theregion of a chemical shift −80 ppm or more and −40 ppm or less, and forwhich the peak half-width value is 0.3 ppm or more and 5.0 ppm or less.

A condensation-type polyorganosiloxane having characteristic [1] of thepreceding characteristics [1] and [2] is preferred in the presentinvention, while a condensation-type polyorganosiloxane havingcharacteristics [1] and [2] is more preferred.

A condensation-type polyorganosiloxane does produce a liberatedcomponent as the condensation reaction progresses, but can be used inthose cases in which, depending on the molding method, this componentdoes not have a substantial influence on the moldability. In this case,the silanol content in the condensation-type polyorganosiloxane isparticularly preferably 0.01 weight % or more and 10 weight % or less.

<1-2. The White Pigment (B)>

A known pigment that does not interfere with resin curing can beselected as appropriate for the white pigment in the present invention.An inorganic material and/or an organic material can be used for thewhite pigment. Here, white denotes colorlessness and the absence oftransparency. Thus, it refers to the color that can cause the diffusereflection of incident light by a substance that does not exhibit aspecific absorption wavelength in the visible region.

Inorganic particles that can be used as the white pigment can beexemplified by metal oxides such as alumina (also referred to below as“finely divided alumina powder” or “aluminum oxide”), silicon oxide,titanium oxide (titania), zinc oxide, magnesium oxide, and so forth;metal salts such as calcium carbonate, barium carbonate, magnesiumcarbonate, barium sulfate, aluminum hydroxide, calcium hydroxide,magnesium hydroxide, and so forth; as well as boron nitride, aluminawhite, colloidal silica, aluminum silicate, zirconium silicate, aluminumborate, clay, talc, kaolin, mica, synthetic mica, and so forth.

Finely divided organic particles that can be used as the white pigmentcan be exemplified by resin particles such as fluororosin particles,guanamine resin particles, melamine resin particles, acrylic resinparticles, silicone resin particles, and so forth, but there is nolimitation to any of the preceding. Viewed from the perspective ofobtaining a high whiteness, a high light reflection activity even atsmall amounts, and resistance to deterioration, alumina, titanium oxide,and zinc oxide are particularly preferred among the preceding. Viewedfrom the perspective of raising the thermal conductivity of the curedmaterial, alumina and boron nitride are particularly preferred. Aluminais particularly preferred also from the perspective of obtaining a highlight reflection action for near-ultraviolet radiation with littledeterioration induced by the near-ultraviolet radiation.

A single one of the preceding may be used or a mixture of two or more ofthe preceding may be used.

When titanium oxide is used, it may be incorporated to a degree thatdoes not bring out the problems with photocatalysis, dispersibility, orwhiteness.

The titanium oxide can be specifically exemplified by the TA series andTR series from Fuji Titanium Industry Co., Ltd., and the TTO series, MCseries, CR-EL series, PT series, ST series, and FTL series from IshiharaSangyo Kaisha, Ltd. The alumina can be specifically exemplified by theA30 series, AN series, A40 series, MM series, LS series, and AHP seriesfrom Nippon Light Metal Co., Ltd.; “Admafine Alumina” type AO-5 and AO-8from Admatechs Co., Ltd.; the CR series from Baikowski Japan Co., Ltd.;Taimicron from Taimei Chemicals Co., Ltd.; alumina powder with adiameter of 10 μm² from Aldrich; the A-42 series, A-43 series, A-50series, AS series, AL-43 series, AL-47 series, AL-160SG series, A-170series, and AL-170 series from Showa Denko Kabushiki Kaisha; and the AMseries, AL series, AMS series, AES series, AKP series, and AA seriesfrom Sumitomo Chemical Co., Ltd. The zirconia can be specificallyexemplified by UEP-100 from Daiichi Kigenso Kagaku Kogyo Co., Ltd. Thezinc oxide can be specifically exemplified by JIS grade 2 zinc oxidefrom HakusuiTech Co., Ltd.

A larger difference between the refractive index of thepolyorganosiloxane (A) and the refractive index of the white pigment (B)provides a higher whiteness, even at small amounts of addition of thewhite pigment, and makes it possible to obtain a better reflection andscattering efficiency for the molded resin for a semiconductorlight-emitting device. The polyorganosiloxane (A) preferably has arefractive index of approximately 1.41, and alumina particles having arefractive index of 1.76 are preferably used as the white pigment (B).The refractive index of the polyorganosiloxane (A) is preferably atleast 1.40 from the standpoint of the hardness of the resin, but ispreferably not more than 1.50 because smaller differences with therefractive index of alumina result in a declining reflectivity and adeclining heat resistance.

The white pigment in the present invention is preferably alumina becausealumina has a high light reflecting activity for near-ultravioletradiation and undergoes little near-ultraviolet-induced deterioration.Alumina exhibits a low absorption capacity for ultraviolet radiation andfor this reason is well adapted for use in combination with alight-emitting element that emits light in the ultraviolet tonear-ultraviolet. In the present invention, alumina denotes the oxide ofaluminum, and, while its crystalline form is not critical, α-alumina,which has such properties as a high chemical stability, a high meltingpoint, a high mechanical strength, a high hardness, and a highelectrical insulation resistance, is well suited for use.

When alumina is used for the white pigment in the present invention, thecrystallite size of the alumina crystals is preferably 500 Å or more and2,000 Å or less, more preferably 700 Å or more and 1,500 Å or less, andparticularly preferably 900 Å or more and 1,300 Å or less. Here,crystallite denotes the largest aggregate that can be regarded as asingle crystal.

The primary particle diameter of the alumina being in the rangeindicated above and the crystallite size of the alumina crystals beingin the range indicated above mean that the primary particle size isdifferent from the crystallite size, that is, that a primary particle iscomposed of a plurality of crystallites.

The crystallite size of the alumina crystals is preferably in the rangeindicated above because this results in little wear of the piping,screw, mold, and so forth, during molding, and also inhibits thewear-induced incorporation of impurities.

The crystallite size can be checked by X-ray diffraction measurements.When the alumina exhibits crystallinity, a peak is generated in theX-ray diffraction measurement at a position determined in conformity tothe crystal form. The crystallite diameter (crystallite size) can becalculated according to the Scherrer equation from the half-width valueof this peak.

The presence as an impurity of elements other than aluminum and oxygenin the alumina is disfavored as this can lead to coloration due toabsorption in the visible light region. For example, when chromium ispresent, even in trace amounts, this is generally called a ruby and ared color is taken on; when iron or titanium is present as an impurity,this is generally called a sapphire and a blue color is displayed. Thealumina used in the present invention preferably has a content ofchromium, iron, and titanium of not more than 0.02 weight % each andmore preferably not more than 0.01 weight % each.

As noted above, a higher thermal conductivity for the cured material ispreferred for the material of the present invention for a molded resin,and the use of at least 98% pure alumina is preferred for raising thethermal conductivity while the use of at least 99% pure alumina is morepreferred and the use of low soda alumina is particularly preferred. Theuse of boron nitride is also preferred for raising the thermalconductivity, and the use of at least 99% pure boron nitride isparticularly preferred.

Titanium oxide can also be suitably used as the white pigment inparticular in semiconductor light-emitting devices that use alight-emitting element that has a peak light emission wavelength at 420nm or greater. While titanium oxide (titania) does have the ability toabsorb ultraviolet radiation, due to its large refractive index andstrong light scattering ability it has a high reflectivity for light atwavelengths of 420 nm and above and readily exhibits strong reflectioneven at small amounts of addition. The rutile type is preferred for thewhite pigment of the present invention because it is more stable at hightemperatures, has a higher refractive index, and has a relatively higherlight resistance than the anatase type, which is unstable at hightemperatures and exhibits a large capacity to absorb ultravioletradiation and a high photocatalytic activity. The use of rutile typethat has been surface-coated with a thin film of silica or alumina isparticularly preferred with the goal of restraining the photoactivity.

Alumina and titanium oxide may be used in combination since titaniumoxide has a high refractive index and thus provides a large refractiveindex difference from polyorganosiloxanes and therefore readily providesstrong reflection even at small amounts of addition. For example, theycan be mixed in proportions that yield a weight ratio of titanium oxideversus alumina (alumina:titanium oxide) of 50:50 to 95:5. The additionof a small amount of titanium oxide to the alumina has the potential toraise the reflectivity for light at wavelengths of 420 nm and greaterover that for the use of alumina by itself and also tends to restrainthe decline in the reflectivity in the case of small proportions of thewhite pigment in the material and in the case of a thin material. Theco-use of titania makes it possible to use the white pigment in smallerproportions in the material, which results in greater freedom in theformulation of the material composition and makes it possible to raisethe amount of loading with components other than the white pigment. Ahigher reflectivity by the thin material is very advantageous in termsof raising the degree of freedom for the shape of the molded resin.Moreover, a high reflectivity for the material even where a largethickness is not possible, as in the case of thin molded resins andfine-structured molded resins, can be expected to have the effect ofincreasing the brightness of the semiconductor light-emitting device.

A surface treatment may be carried out on the white pigment using, forexample, a silane coupling agent. The hardness of the molded resinmaterial as a whole can be improved when a white pigment is used thathas been surface-treated with a silane coupling agent.

<1-2-1. Preferred Shapes for the White Pigment (B)>

The primary particles of the white pigment (B) characteristically havean aspect ratio 1.2 or more and 4.0 or less in the present invention.

The aspect ratio of the white pigment (B) is preferably at least 1.25,more preferably at least 1.3, and even more preferably at least 1.4. Theupper limit, on the other hand, is preferably not more than 3.0, morepreferably not more than 2.5, even more preferably not more than 2.2,particularly preferably not more than 2.0, and most preferably not morethan 1.8.

When the aspect ratio is in the range indicated above, a highreflectivity due to scattering is readily manifested and in particular alarge reflection is obtained for the short wavelength light of thenear-ultraviolet region. This results in an improved LED output for asemiconductor light-emitting device that uses the molded resin underconsideration.

The use of a white pigment having an aspect ratio in the above-indicatedrange is also preferred in terms of the moldability, i.e., a low moldwear is obtained. When the aspect ratio is larger than theabove-indicated range, severe mold wear may occur due to contact withthe angular regions of the pigment particles. Conversely, when a whitepigment is used that has a smaller aspect ratio, mold wear is againprone to occur because the frequency of contact between the mold andpigment is increased due to an increase in the packing density of thepigment in the material. Furthermore, the viscosity of the material canbe easily adjusted when a white pigment having an aspect ratio in theabove-indicated range is used, and adjustment to a viscosity favorablefor molding can provide a material with an excellent moldability, i.e.,the molding cycle can be shortened and flashing can be inhibited.

When, in particular, the aspect ratio is larger than 4.0, it is thendifficult to obtain strong reflection; wear of the plumbing, screw,mold, and so forth, will readily occur during molding; and, due to theincorporation of impurities caused by the wear, the molded resin productis prone to have a reduced reflectivity and is also readily susceptibleto dielectric breakdown.

The aspect ratio is generally used as a convenient method forquantitatively expressing the shape of, for example, a particle, and isdetermined in the present invention by dividing the length of the majoraxis (the largest long diameter) of a particle, as measured byobservation with an electron microscope, e.g., with an SEM, by thelength of the minor axis (the length of the longest part in thedirection perpendicular to the long diameter). In the event of scatteror variation in the length of an axis, a plurality of points (10 points,for example) can be measured by SEM and the length of the axis can bedetermined from their average value. Or, by measuring 30 points or 100points the same result can be obtained from the calculation.

The aspect ratio is an index to whether the shape of the particle isfibrillar or rod-like or is spherical, and a particle with a fibrillarshape has a large aspect ratio while a spherical particle has an aspectratio of 1.0.

By having the aspect ratio be in the range indicated above, the presentinvention excludes spherical and perfectly spherical shapes from theshapes preferred for the white pigment (B). In addition, highlyelongated shapes, because they instead cause a lowering of thereflectivity, are also excluded from the white pigment (B) according tothe present invention. When the aspect ratio is in the range indicatedabove, the white pigment tends to block clearances in the mold andthereby inhibits the occurrence of flashing; with a spherical shape,however, clearances in the mold are traversed and flashing tends tooccur easily.

In the present invention, particles having an aspect ratio encompassedby the previously indicated range preferably account for at least 60volume %, more preferably at least 70 volume %, and particularlypreferably at least 80 volume % of the white pigment (B) as a whole. Theindividual skilled in the art will naturally understand that this is nota case where the entire white pigment (B) must necessarily satisfy theaspect ratio range indicated above.

Ordinary methods, e.g., grinding and/or subjecting the white pigment toa surface treatment, may be used to bring the aspect ratio into therange indicated above. This can also be achieved by microfine-sizing bygrinding (pulverizing) the white pigment and/or by producing the whitepigment by calcination.

With regard to chemical composition, the white pigment (B) in thepresent invention encompasses the finely divided inorganicparticles/finely divided organic particles provided above as examples in1-2. In addition, its shape is preferably a (c) crushed shape.

This (c) crushed shape denotes the shape provided when the white pigmentis microfine-sized mainly by grinding (pulverization) and also includesshapes—as provided by a post-grinding treatment—that somewhat take on aroundness having small crystal angles, as well as the nonsphericalpigment shapes produced by, for example, calcination. Thus, the intentis to exclude, from the standpoint of the nature of the productionprocess, white pigment formed with a spherical or perfectly sphericalshape. The material that uses a white pigment having a crushed shapemore readily exhibits a high scattering-induced reflectivity than doesthe material that uses a spherical white pigment and in particularexhibits greater reflection of the short wavelength light in thenear-ultraviolet region (particularly light with a wavelength of 360 nmto 460 nm). It can also be more favorable from an economic standpointthan a spherical pigment. The LED output can thus be improved based onthe preceding in a semiconductor light-emitting device that uses themolded resin under consideration.

The primary particle diameter of the white pigment (B) is preferably 0.1μm or more and 2 μm or less in the present invention. The value of thelower limit is preferably at least 0.15 μm, more preferably at least 0.2μm, and particularly preferably at least 0.25 μm, while the value of theupper limit is preferably not more than 1 μm, more preferably not morethan 0.8 μm, and particularly preferably not more than 0.5 μm.

When the primary particle diameter is in the above-indicated range, thematerial can readily exhibit a high reflectivity because it combines thescattered light intensity with a backscattering tendency and inparticular strongly reflects short wavelength light, e.g., in thenear-ultraviolet region, and is thus preferred.

When the primary particle diameter of the white pigment is too small,the scattered light intensity is low and as a consequence thereflectivity tends to be low; when the primary particle diameter is toolarge, the scattered light intensity is high, but the reflectivity tendsto be small due to the appearance of a forward scattering tendency.

A primary particle diameter in the above-indicated range is alsopreferred from the standpoint of the moldability, e.g., facileadjustment to a viscosity suitable for molding, low mold wear, and soforth. When the primary particle diameter exceeds the range given above,contact with the pigment particles subjects the mold to a large impactand substantial mold wear then tends to occur. When a white pigment isused that has a primary particle diameter below the range given above,the material readily assumes a high viscosity and the loading volume bythe white pigment cannot be raised, and as a result it tends to bedifficult to achieve a balance between the moldability and theproperties of the material, e.g., high reflection.

In particular, the material must be provided with at least a certaindegree of thixotropic nature in order to yield a material suitable foruse in liquid injection molding. A white pigment with a primary particlediameter 0.1 μm or more and 2.0 μm or less has a substantial ability toimpart thixotropic nature when added to the composition, and theviscosity and thixotropic nature can then be easily adjusted to providean easy-to-mold composition that exhibits little flashing or shortmolding.

A combination with a white pigment having a primary particle diameterlarger than 2 μm can also be used in order, for example, to raise thefilling rate for the white pigment in the resin composition.

The primary particle referenced by the present invention is the smallestsolid unit that can be clearly separated from among the other particlesthat make up a powder, and the primary particle diameter denotes theparticle diameter of a primary particle as measured by observation withan electron microscope, e.g., an SEM. A secondary particle, on the otherhand, refers to an aggregated particle formed by the aggregation ofprimary particles, and the median diameter of the secondary particlesrefers to the particle diameter measured using, for example, a particledistribution analyzer, with the powder dispersed in a suitabledispersing medium (for example, water in the case of alumina). Whenthere is scatter in the primary particle diameter, the SEM observationcan be performed at several points (for example, 10 points) and theaverage value thereof can be determined and used as the particlediameter. When a particular particle diameter is nonspherical in themeasurement, the longest length, i.e., the length of the major axis, isused for the particle diameter.

The aspect ratio and primary particle diameter of the white pigment canbe measured even after molding (post-curing). A cross section of themolded product can be observed with an electron microscope, e.g., withan SEM, and the primary particle diameter and aspect ratio can bemeasured on the white pigment exposed in the cross section.

This is determined in the present invention by dividing the length ofthe major axis (the largest long diameter) of a particle, as measured byobservation with an electron microscope, e.g., with an SEM, by thelength of the minor axis (the length of the longest part in thedirection perpendicular to the long diameter). In the event of scatteror variation in the length of an axis, a plurality of points (10 points,for example) can be measured by SEM and the length of the axis can bedetermined from their average value. Or, 30 points or 100 points can bemeasured and the result can be used from the same calculation.

The median diameter of the secondary particles (also referred to belowas the “secondary particle diameter”) of the aforementioned whitepigment is preferably at least 0.2 μm and more preferably at least 0.3μm. The upper limit is preferably not more than 10 μm, more preferablynot more than 5 μm, and even more preferably not more than 2 μm.

A preferred material in terms of moldability can be readily obtainedwhen the secondary particle diameter is in the above-indicated range. Inaddition, adjustment to a viscosity suitable for molding can be easilycarried out and there is little mold wear. Moreover, the appearance offlashing is inhibited because the ability of the white pigment to passthrough clearances in the mold is inhibited, and the occurrence ofproblems during molding is inhibited because mold gate clogging isinhibited. When the secondary particle diameter exceeds theabove-indicated range, the material tends to become nonuniform due tosedimentation of the white pigment and the moldability is impaired dueto mold wear and gate clogging and the uniformity of reflection by thematerial is impaired.

A combination with a white pigment having a secondary particle diameterlarger than 10 μm can also be used in order, for example, to raise thefilling rate for the white pigment in the resin composition. The mediandiameter, refers to the particle diameter at the point where the volumebased particle size distribution curve in cumulative % intersects withthe horizontal axis at 50% and is typically referred to as the 50%particle diameter (D₅₀) or the median diameter.

The ratio y/x of the median diameter y of the secondary particles to theprimary particle diameter x of the white pigment (B) is generally atleast 1 in the present invention and is preferably larger than 1 andmore preferably is at least 1.2, and is generally not more than 10 andpreferably not more than 5.

By having the ratio y/x of the median diameter y of the secondaryparticles to the primary particle diameter x be in the above-indicatedrange, white pigment formed in a spherical or perfectly spherical shape(that is, there is almost no aggregation of primary particles and theprimary particle diameter and the median diameter of the secondaryparticles are approximately equal) is excluded from the preferred shapesfor the white pigment (B).

When the ratio y/x of the median diameter y of the secondary particlesto the primary particle diameter x is in the above-indicated range, ahigh reflectivity is readily manifested due to scattering and inparticular short wavelength light in the near-ultraviolet region issubstantially reflected. This makes it possible to raise the LED outputin a semiconductor light-emitting device that uses the molded resinunder consideration. Moreover, adjustment to a material viscositysuitable for molding is also easily carried out.

<1-2-2. The Amount of Addition for the White Pigment (B)>

The content of the white pigment (B) in the molded resin material for asemiconductor light-emitting device in the present invention is selectedas appropriate as a function of the particle diameter and type of thepigment used and the difference between the refractive indexes of thepolyorganosiloxane and pigment. Expressed with respect to 100 weightparts of the polyorganosiloxane (A), the content of the white pigment(B) is generally at least 20 weight parts, preferably at least 50 weightparts, and more preferably at least 100 weight parts and is generallynot more than 900 weight parts, preferably not more than 600 weightparts, and more preferably not more than 400 weight parts.

An excellent reflectivity and moldability are obtained within theabove-indicated range. At below the lower limit indicated above, lighttransmission tends to occur and the reflection efficiency of thesemiconductor light-emitting device tends to decline. At above the upperlimit, the moldability tends to decline due a deterioration in thefluidity of the material.

In particular, the material must be provided with at least a certaindegree of thixotropic nature in order to yield a material suitable foruse in liquid injection molding. When a white pigment with a primaryparticle diameter 0.1 μm or more and 2.0 μm or less is incorporated inthe composition, a substantial increasing viscosity occurs and a largethixotropic nature imparting effect is obtained. The incorporation of atleast 30 weight %, with reference to the composition as a whole, of awhite pigment with such a shape can provide an easily moldable materialthat exhibits little flashing or short molding and also facilitatesadjustment of the viscosity and thixotropic nature.

In order, in addition, to control the thermal conductivity of thematerial for a molded resin into the range 0.4 or more and 3.0 or less,vide infra, the addition is preferred, expressed with reference to thetotal weight of the material for a molded resin, of 40 weight parts ormore and 90 weight parts or less of alumina as the white pigment (B).Or, the addition is preferred, expressed with reference to the totalweight of the material for a molded resin, of 30 weight parts or moreand 90 weight parts or less of boron nitride as the white pigment (B).Alumina and boron nitride may also be used in combination.

<1-3. The Curing Catalyst (C)>

The curing catalyst (C) in the present invention is a catalyst thatcures the polyorganosiloxane (A). The polyorganosiloxane cures with thepolymerization reaction being accelerated by the catalyst. This catalystis an addition polymerization catalyst or a polycondensation catalystdepending on the curing mechanism for the polyorganosiloxane.

The addition polymerization catalyst is a catalyst for accelerating thehydrosilylation addition reaction between the alkenyl group in component(C1) and the hydrosilyl group in component (C2), and this additionpolymerization catalyst can be exemplified by platinum group metalcatalysts such as platinum-based catalysts, e.g., platinum black,platinic chloride, chloroplatinic acid, the reaction product ofchloroplatinic acid and a monohydric alcohol, a chloroplatinicacid/olefin complex, and platinum bisacetoacetate; palladium-basedcatalysts; and rhodium-based catalysts. The amount of incorporation ofthis addition polymerization catalyst (C3) can be a catalytic amount,and, expressed as the platinum group metal with reference to the totalweight of (C1) and (C2), is generally at least 1 ppm and preferably atleast 2 ppm and generally is not more than 100 ppm, preferably not morethan 50 ppm, and more preferably not more than 20 ppm. Operating inaccordance with the preceding can provide a high catalytic activity.

An acid such as hydrochloric acid, nitric acid, sulfuric acid, or anorganic acid, or an alkali such as ammonia or an amine, or a metalchelate compound can be used as the polycondensation catalyst, and ametal chelate compound containing at least one selection from Ti, Ta,Zr, Al, Hf, Zn, Sn, and Pt can be favorably used as the polycondensationcatalyst. Among the preceding, the metal chelate compound preferablycontains at least one selection from Ti, Al, Zn, and Zr, wherein the useof a metal chelate compound that contains Zr is more preferred.

These catalysts are selected considering the stability when incorporatedin the molded resin material for a semiconductor light-emitting device,the film hardness, the nonyellowing performance, and the curability.

The amount of incorporation of the polycondensation catalyst, expressedwith reference to the total weight of the components represented byformula (3) and/or (4) above, is generally at least 0.01 weight % andpreferably at least 0.05 weight %, while the upper limit is generallynot more than 10 weight % and preferably not more than 6 weight %.

When the amount of addition is in the range given above, the moldedresin material for a semiconductor light-emitting device has anexcellent curability and storage stability and the quality of the moldedresin product is also excellent. Problems may appear with the storagestability of the molded resin material when the amount of additionexceeds the upper limit value. At below the lower limit value, longcuring times are encountered and the molded resin productivity declinesand there is also a tendency for the quality of the molded resin to bereduced due to uncured components.

<1-4. The Cure Rate Controlling Agent (D)>

The material of the present invention for a molded resin for asemiconductor light-emitting device preferably also contains a cure ratecontrolling agent (D). This cure rate controlling agent is used tocontrol the cure rate during molding of the molded resin material inorder to improve its molding efficiency and can be exemplified byretarders and hardening accelerators.

The retarders can be exemplified by compounds that contain analiphatically unsaturated bond, organophosphorus compounds, organosulfurcompounds, nitrogenous compounds, tin compounds, organoperoxides, and soforth, and these may be used in combination.

The compounds that contain an aliphatically unsaturated bond can beexemplified by propargyl alcohols such as 3-hydroxy-3-methyl-1-butyne,3-hydroxy-3-phenyl-1-butyne, and 1-ethynyl-1-cyclohexanol; ene-ynecompounds; and maleic acid esters such as dimethyl maleate. Compoundsthat contain a triple bond are preferred among these compoundscontaining an aliphatically unsaturated bond. The organophosphoruscompounds can be exemplified by triorganophosphites, diorganophosphines,organophosphines, and triorganophosphites. The organosulfur compoundscan be exemplified by organomercaptans, diorgano sulfides, hydrogensulfide, benzothiazole, thiazole, and benzothiazole disulfide. Thenitrogenous compounds can be exemplified by ammonia, primary to tertiaryalkylamines, arylamines, urea, and hydrazine. The tin compounds can beexemplified by stannous halide dihydrates and stannous carboxylates. Theorganoperoxides can be exemplified by di-t-butyl peroxide, dicumylperoxide, benzoyl peroxide, and t-butyl perbenzoate.

Among the retarders given above, benzothiazole, thiazole, dimethylmaleate, 3-hydroxy-3-methyl-1-butyne, and 1-ethynyl-1-cyclohexanol arepreferred for their excellent retardation activity and ease of reagentacquisition.

Various amounts of addition can be set for the retarder, but, expressedper 1 mol of the curing catalyst (C) used, the lower limit on the amountof addition is preferably at least 10⁻¹ mol and more preferably at least1 mol and the upper limit on the amount of addition is preferably notmore than 10³ mol and more preferably not more than 50 mol. A single oneof these retarders may be used or two or more may be used incombination.

There are no particular limitations on the hardening accelerator otherthan that it have the ability to cure the heat-curable resin, and thehardening accelerator can be exemplified by imidazoles, dicyandiamidederivatives, dicarboxylic acid dihydrazides, triphenylphosphine,tetraphenylphosphonium tetraphenylborate, 2-ethyl-4-methylimidazoletetraphenylborate, and1,8-diazabicyclo[5.4.0]undecene-7-tetraphenylborate. The use of theimidazoles is preferred among the preceding because they exhibit a highreaction-promoting activity.

The imidazoles can be exemplified by 2-methylimidazole,2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and1-cyanoethyl-2-phenylimidazolium trimellitate, and are available underthe product names 2E4MZ, 2PZ-CN, and 2PZ-CNS (Shikoku ChemicalsCorporation). The amount of addition of the hardening accelerator ispreferably 0.1 weight part or more and 10 weight parts or less per 100weight parts of the total of the heat-curable polyorganosiloxane resin(A) and the curing catalyst (C).

The specification of the type and amount of incorporation of the curerate controlling agent as indicated above makes it easy to mold thematerial for a molded resin. For example, advantages accrue such asproviding a high mold filling ratio, eliminating leakage from the moldduring molding by injection molding, and providing resistance toflashing.

<1-5. Other Components>

Insofar as the essential features of the present invention are notimpaired, the material for a molded resin for a semiconductor device mayoptionally contain, in any proportion and any combination, one or two ormore components other than the polyorganosiloxane (A), white pigment(B), curing catalyst (C), and cure rate controlling agent (D).

For example, solid particles can be incorporated as a fluiditycontrolling agent (E) with the objective of controlling thesedimentation of the white pigment and/or controlling the fluidity ofthe material for a molded resin for a semiconductor light-emittingdevice. The fluidity controlling agent (E) should be a particle that issolid from normal temperature to around the molding temperature and thatthrough its incorporation provides a higher viscosity for the materialfor a molded resin, but is not otherwise particularly limited. However,it preferably has no ability, or only a very small ability, to absorblight from the light-emitting element or light at a phosphor-convertedwavelength, does not significantly lower the reflectivity of thematerial, and is very durable and exhibits little light- or heat-induceddiscoloration or degradation. Specific examples are finely dividedsilica particles, quartz beads, glass beads, inorganic fibers such asglass fiber, boron nitride, and aluminum nitride. Moreover, a whitepigment that does not satisfy one of the following characteristics (a)and (b), or that satisfies neither of them, such as a fibrous alumina,can be incorporated separately from the white pigment already describedabove.

(a) The primary particle aspect ratio is 1.2 or more and 4.0 or less.(b) The primary particle diameter is 0.1 μm or more and 2.0 μm or less.

Finely divided silica particles, which have a significant ability toimpart thixotropic nature, are preferred for use among the precedingbecause they provide facile control of the viscosity and thixotropicnature of the composition. Quartz beads, glass heads, and glass fiberare preferred not only because they can function as a fluiditycontrolling agent, but also because they can be expected to raise thestrength and toughness of the post-thermoset material and to lower thelinear expansion coefficient of the material, and they may be used aloneor in combination with finely divided silica particles.

There are no particular limitations on the finely divided silicaparticles used by the present invention, but they will have a specificsurface area by the BET method generally of at least 30 m²/g, preferablyat least 50 m²/g, and more preferably at least 100 m²/g, and generallynot more than 300 m²/g and preferably not more than 200 m²/g. When thespecific surface area is too small, no effect is seen from the additionof the finely divided silica particles; when the specific surface areais too large, it becomes very difficult to effect dispersion in theresin. Finely divided silica particles may be used that have beensubjected to a surface hydrophobicization by, for example, reacting asurface modifier with the silanol groups that are present on the surfaceof the hydrophilic finely divided silica particles.

The surface modifier can be exemplified by alkylsilane compounds andspecifically by dimethyldichlorosilane, hexamethyldisilazane,octylsilane, and dimethylsilicone oil.

The finely divided silica particles can be exemplified by fumed silica.Fumed silica is produced by the oxidation and hydrolysis of SiCl₄ gas inan 1100 to 1400° C. flame provided by the combustion of a mixed gas ofH₂ and O₂. The primary particles in fumed silica are spherical ultrafineparticles that have an average particle diameter of about 5 to 50 nm andthat have amorphous silicon dioxide (SiO₂) as their main component;these primary particles aggregate with each other to form secondaryparticles having a particle diameter of several hundred nanometers.Fumed silica, because it is an ultrafine particulate and is produced byquenching, has a surface structure that is in a chemically active state.

“Aerosil” (registered trademark) from Nippon Aerosil Co., Ltd., is aspecific example, and examples of hydrophilic Aerosil (registeredtrademark) are “90”, “130”, “150”, “200”, and “300”, while examples ofhydrophobic Aerosil (registered trademark) are “PX50”, “NAX50”, “NY90G”,“RY50”, “NY50”, “R8200”, “R972”, “R972V”, “R972CF”, “R974”, “R202”,“R805”, “R812”, “R812S”, “RY200”, “RY200S”, and “RX200”.

A polyorganosiloxane that functions as a liquid increasing viscosityagent may be incorporated as a portion of the polyorganosiloxane (A) inorder to adjust the viscosity of the material for a molded resin. Thefollowing can be incorporated as a liquid increasing viscosity agent: astraight-chain polyorganosiloxane that has a viscosity at 25° C.generally 0.001 Pa·s or more and 3 Pa·s or less, preferably 0.001 Pa·sor more and 1 Pa·s or less, and more preferably 0.001 Pa·s or more and0.7 Pa·s or less, that has a hydroxyl value generally of from 1.0×10⁻²to 10.3×10⁻⁵ mol/g, preferably from 1.0×10⁻² to 9.5×10⁻⁵ mol/g, and morepreferably from 1.0×10⁻² to 7.7×10⁻⁵ mol/g, and that has at least onesilicon-bonded hydroxyl group (i.e., the silanol group) in eachmolecule.

This hydroxyl group-containing straight-chain organopolysiloxane used asa liquid increasing viscosity agent should not contain a functionalgroup that participates in the hydrosilylation addition reaction, e.g.,an alkenyl group and/or the SiH group, in the molecule, and the hydroxylgroup present in the molecule may be bonded to the silicon at themolecular chain terminals, or may be bonded to the silicon innonterminal position on the molecular chain (i.e., along the molecularchain), or may be bonded in both positions. A straight-chainorganopolysiloxane containing the hydroxyl group bonded to the siliconat both molecular chain terminals (that is, anα,ω-dihydroxydiorganopolysiloxane) is preferred.

The silicon-bonded organic groups here can be exemplified by monovalenthydrocarbon groups such as alkyl groups, e.g., methyl, ethyl, propyl,and so forth, and aryl groups, the phenyl group and so forth. Thediorganosiloxane repeat unit constituting the main chain of theorganopolysiloxane under consideration is preferably a single selectionor, a combination of two or more selections from the dimethylsiloxaneunit, diphenylsiloxane unit, methylphenylsiloxane unit, and so forth.Specific examples are α,ω-dihydroxydimethylpolysiloxane,α,ω-dihydroxydiphenylpolysiloxane,α,ω-dihydroxymethylphenylpolysiloxane,α,ω-dihydroxy(dimethylsiloxane/diphenylsiloxane) copolymer, andα,ω-dihydroxy(dimethylsiloxane/methylphenylsiloxane) copolymer.

The amount of incorporation of the polyorganosiloxane functioning as aliquid increasing viscosity agent, expressed per 100 weight parts of theentire polyorganosiloxane (A), is generally 0 to 10 weight parts,preferably 0.1 to 5 weight parts, and more preferably approximately 0.5to 3 weight parts.

An inorganic fiber, e.g., glass fiber, may be incorporated with theobjective of raising the strength and toughness of thepost-thermosetting material. For example, boron nitride, aluminumnitride, or fibrous alumina, which have high thermal conductivities, maybe incorporated separately from the white pigment already describedabove in order to raise the thermal conductivity. In addition, quartzbeads, glass beads, and so forth, may be incorporated with the objectiveof lowering the linear expansion coefficient of the cured material.

When these are added, the intended effect is not obtained when theiramount of incorporation is too low, while an amount of incorporationthat is too large raises the viscosity of the material for a moldedresin for a semiconductor light-emitting device and thus affects theprocessability. For these reasons, their amount of incorporation shouldbe selected as appropriate from within a range where a satisfactoryeffect is developed and the processability of the material is notimpaired. This is generally not more than 500 weight parts andpreferably not more than 200 weight parts per 100 weight parts of thepolyorganosiloxane.

The following, for example, may also be incorporated, in a range thatdoes not impair the effects and objects of the present invention, in theaforementioned material for a molded resin: an ion migration(electrochemical migration) inhibitor, ageing inhibitor, radicalinhibitor, ultraviolet absorber, adhesion promoter, flame retardant,surfactant, storage stabilizer, ozone degradation inhibitor,photostabilizer, increasing viscosity agent, plasticizer, couplingagent, oxidation inhibitor, heat stabilizer, agent that provideselectroconductivity, static inhibitor, radiation-blocking agent,nucleating agent, phosphorus-based peroxide decomposer, lubricant,pigment, metal inactivator, and property controlling agent.

Silane coupling agents are an example of the coupling agent. The silanecoupling agent should contain in each molecule at least one hydrolyzablesilicon group and at least one functional group reactive with organicgroups, but is not otherwise particularly limited. Considered from thestandpoint of the handling characteristics, the group reactive withorganic groups is preferably at least one functional group selected fromthe epoxy group, methacryl group, acryl group, isocyanate group,isocyanurate group, vinyl group, and carbamate group, while consideredfrom the standpoint of the curability and adhesiveness the epoxy group,methacryl group, and acryl group are particularly preferred. Consideredfrom the standpoint of the handling characteristics, the hydrolyzablesilicon group is preferably an alkoxysilyl group, while the methoxysilylgroup and ethoxysilyl group are particularly preferred in terms ofreactivity.

Examples of preferred silane coupling agents are alkoxysilanes havingthe epoxy functional group, e.g., 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropyltriethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and alkoxysilanes bearingthe methacryl group or acryl group, e.g.,3-methacryloxypropyltrimethoxysilane,3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane,3-acryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxymethyltriethoxysilane, acryloxymeLhyltrimethoxysilane, andacryloxymethyltriethoxysilane.

The preferred contents of the previously described components (A) to (E)in the material of the present invention for a molded resin for asemiconductor light-emitting device are as follows.

The content of the polyorganosiloxane (A) in the material of the presentinvention for a molded resin should generally be in a range that enablesuse as a material for a molded resin, but is not otherwise limited, and,expressed with reference to the material as a whole, is generally 10weight % or more and 50 weight % or less, preferably 15 weight % or moreand 40 weight % or less, and more preferably 20 weight % or more and 35weight % or less. When the cure rate controlling agent (D) and liquidincreasing viscosity agent, which is an additional component, present inthe material are polyorganosiloxanes, they are included in the contentof (A).

The content of the white pigment (B) in the material of the presentinvention for a molded resin should generally be in a range that enablesuse as a material for a molded resin, but is not otherwise limited, and,expressed with reference to the material as a whole, is generally from30 weight % or more and 85 weight % or less, preferably 40 weight % ormore and 80 weight % or less, and more preferably 45 weight % or moreand 70 weight % or less, in case of that alumina is used as the whitepigment (B).

The content of the fluidity controlling agent (E) in the material of thepresent invention for a molded resin should be in a range that does notimpair the effects of the present invention, but is not otherwiselimited, and, expressed with reference to the material as a whole, isgenerally not more than 80 weight, preferably 2 weight % or more and 70weight % or less, and more preferably 5 weight % or more and 60 weight %or less.

The ratio of the total amount of the white pigment (B) and fluiditycontrolling agent (E) to the molded resin material as a whole ispreferably at least 50 weight %, more preferably at least 60 weight %,and particularly preferably at least 65 weight %, and is preferably notmore than 85 weight % and more preferably not more than 80 weight.

<1-6. The Viscosity of the Material for a Molded Resin>

The material of the present invention for a molded resin for asemiconductor light-emitting device preferably has a viscosity at 25° C.and a shear rate of 100 s⁻¹ of 10 Pa·s or more and 10,000 Pa·s or less.Viewed from the perspective of the molding efficiency during molding ofthe molded resin for a semiconductor device, this viscosity is morepreferably 50 Pa·s or more and 5,000 Pa·s or less, even more preferably100 Pa·s or more and 2,000 Pa·s or less, and particularly preferably 150Pa·s or more and 1,000 Pa·s or less.

In addition, viewed from the standpoint of the thixotropic nature, asdiscussed below, the material of the present invention for a moldedresin for a semiconductor light-emitting device has a ratio (1 s⁻¹/100s⁻¹) of the viscosity at 25° C. and a shear rate of 1 s⁻¹ to theviscosity at 25° C. and a shear rate of 100 s⁻¹ preferably of at least15, more preferably of at least 20, and particularly preferably of atleast 30. The upper limit, on the other hand, is preferably not morethan 500 and more preferably not more than 300.

In addition, the material of the present invention for a molded resinfor a semiconductor light-emitting device particularly preferably has aviscosity at 25° C. and a shear rate of 100 s⁻¹ of not more than 1,000Pa·s and a ratio (1 s⁻¹/100 s⁻¹) of the viscosity at 25° C. and a shearrate of 1 s⁻¹ to the viscosity at 25° C. and a shear rate of 100 s⁻¹ ofat least 15.

In order to provide a material that exhibits a good moldability, thematerial must be endowed with a certain degree of thixotropic nature,and when the viscosity at 25° C. and a shear rate of 100 s⁻¹ is 10 Pa·sor more and 10,000 Pa·s or less, and the ratio of the viscosity at ashear rate of 1 s⁻¹ to the viscosity at a shear rate of 100 s⁻¹ is atleast 15, a material is provided that exhibits little flashing and shortmolding (incomplete filling), that supports a shortening of the moldingcycle and the total time for the material in molding, and that has ahigh molding efficiency and facilitates stable molding.

Particularly in the case of LIM molding, which uses a liquid resinmaterial, flashing easily occurs caused by material oozing out from verysmall clearances in the mold, and this has necessitated apost-processing step to remove the flash. Another problem, on the otherhand, has been the easy occurrence of short molding (incomplete filling)when the clearances in the mold are reduced in size in order to inhibitthe occurrence of flashing. These problems can be solved when theviscosity of the material for a molded resin is in the range indicatedabove, and the LIM molding of the molded resin can then be easilycarried out with a good moldability. When the viscosity at a shear rateof 100 s⁻¹ exceeds 10,000 Pa·s, mold filling becomes unsatisfactorybecause the resin exhibits poor flow and the molding cycle duringinjection molding is lengthened due to the time required for materialfeed, and the molding efficiency thus tends to decline. When thisviscosity is less than 10 Pa·s, flashing is produced because thematerial leaks from clearances in the mold and it is also difficult tocarry out stable molding because the injection pressure readily escapesthrough clearances in the mold, and the molding efficiency thus tends todecline. Particularly in the case of small moldings, the post-processingrequired to remove flash becomes quite problematic and preventingflashing then becomes critical for the moldability.

When the ratio of the viscosity at 25° C. and a shear rate of 1 s⁻¹ tothe viscosity at 25° C. and a shear rate of 100 s⁻¹ is less than 15,i.e., when the viscosity at a shear rate of 1 s⁻¹ is relatively small,controlling molding can be problematic for the following reasons: thematerial also easily penetrates into clearances in the molding deviceand the mold and flashing is very prone to occur; dripping from thenozzle readily occurs; and it is difficult to transmit the injectionpressure to the material, which impedes the stable execution of molding.While resin leakage at the parting line of the sprue tends to be aproblem in LIM molding, the adjustment into the viscosity range of thepresent invention also has the effect of preventing this resin leakage.

This viscosity at 25° C. and a shear rate of 100 s⁻¹ and viscosity at25° C. and a shear rate of 1 s⁻¹ can be measured using, for example, anARES-G2 strain-controlled rheometer (from TA Instruments Japan Inc.).

A certain degree of thixotropic nature must be imparted to the materialin order to control the aforementioned viscosity and provide a materialsuitable for use in liquid injection molding (LIM molding). Asubstantial increasing viscosity occurs and a large thixotropic natureimparting effect is obtained when finely divided particles in themicroscopic range (primary particle diameter 0.1 μm or more and 2.0 μmor less) are incorporated in the material. As a consequence, thethixotropic nature of the composition is easily controlled when a whitepigment (B) having a primary particle diameter 0.1 μm or more and 2.0 μmor less is used and/or when a fluidity controlling agent (E) in themicroscopic range, such as fumed silica with its large specific surfacearea, is used. Specifically, the incorporation is preferred of at least30 weight % of the white pigment (B) having a primary particle diameter0.1 μm or more and 2.0 μm or less, while the viscosity of the materialcan be controlled into the previously indicated range even morepreferably by the incorporation of the combination of the white pigment(B) with a fluidity controlling agent (E) that is not a white pigment,such as a fumed silica or quartz beads, at a total of 50 to 85 weight %for the combination.

When a white pigment is used that has a median diameter for thesecondary particles greater than 2 μm, and particularly when a whitepigment is used that has a median diameter of at least 5 μm, it ispreferably used in combination with a fluidity controlling agent in themicroscopic range with its large thixotropic nature imparting effect.However, when the primary particle diameter of the white pigment (B)itself is sufficiently small, it will also be possible to use only thewhite pigment without the combination with a fluidity controlling agent,or it may be combined with a fluidity controlling agent that has arelatively large median diameter of several micrometers or more.

<1-7. The Thermal Conductivity of the Material for a Molded Resin>

The material of the present invention for a molded resin for asemiconductor light-emitting device has a thermal conductivity whencured preferably 0.4 or more and 3.0 or less, and more preferably 0.6 ormore and 2.0 or less. The thermal conductivity when cured can bemeasured using, for example, an ai-Phase Mobile (from the ai-Phase Co.,Ltd.).

Here, “when cured” refers to the execution of thermosetting for 4minutes at 180° C.

Heat is produced in a semiconductor light-emitting device by the lightthat is emitted from the semiconductor light-emitting element, andlarger amounts of heat are generated in particular in the case ofhigh-output elements. In such cases, the phosphor layer adjacent to themolded resin undergoes heat-induced deterioration and the durability ofthe device is ultimately diminished.

With respect to this problem, the present inventors discovered that byhaving the thermal conductivity when cured, i.e., when the molded resinhas been made by molding, be in the previously indicated range, thethermal radiation characteristics for the heat generated by the lightemitted from the semiconductor light-emitting element are improved forthe molded resin and the semiconductor light-emitting device constructedusing it, and as a consequence the durability of the device is alsoimproved.

When this thermal conductivity is less than 0.4, the phosphor layerpresent in the device tends to undergo thermal degradation due to theheat generated by the light emitted from the semiconductorlight-emitting element in the device.

The thermal conductivity here can be controlled into the above-indicatedrange by the use of alumina or boron nitride for the white pigment (B)present in the material for a molded resin for a semiconductorlight-emitting device.

<1-8. The Reflectivity of the Molded Resin>

The molded resin that uses the molded resin material of the presentinvention preferably can maintain a high reflectivity for visible light.Specifically, the reflectivity for light at 460 nm is preferably atleast 80% and more preferably is at least 90%. In addition, thereflectivity for light at a wavelength of 400 nm is preferably at least60%, more preferably at least 80%, and even more preferably at least90%.

This reflectivity by the molded resin refers to the reflectivitymeasured on the 0.4 mm-thick molding provided by thermally curing andmolding the molded resin material of the present invention. This thermalcuring can be carried out, for example, by curing for 4 minutes at 180°C. under a pressure of 10 kg/cm².

The reflectivity of the molded resin can be controlled through, forexample, the type of resin (for example, the reflectivity can becontrolled by changing the refractive index of the resin), the type offiller, and the particle diameter and content of the filler.

<2. Methods for Molding the Molded Resin for a SemiconductorLight-Emitting Device>

The method for molding the molded resin of the present invention for asemiconductor light-emitting device can be exemplified by compressionmolding methods, transfer molding methods, and injection moldingmethods. Among these, injection molding methods and particularly liquidinjection molding (LIM molding) methods are preferred because they donot produce wasted cured material and do not require secondaryprocessing (that is, are resistant to the generation of flash) andbecause they offer the major advantages of automation of the process formolding the molded resin, a shortening of the molding cycle, andenabling cost reduction for the molded product. When LIM molding andtransfer molding are compared, LIM molding offers the advantages of agreater freedom for the shape of the molding and a relativelyinexpensive molding device and mold.

The injection molding methods can be carried out using an injectionmolding machine. The cylinder setting temperature may be selected asappropriate in conformity to the material, but is generally not morethan 100° C., preferably not more than 60° C., and more preferably notmore than 60° C. The mold temperature is 80° C. or more and 300° C. orless, and preferably is 100° C. or more and 250° C. or less, and morepreferably is 120° C. or more and 200° C. or less. The injection timewill vary with the material, but is generally several seconds or notmore than 1 second. The molding time may be selected as appropriate inconformity to the gelation rate and cure rate of the material, but isgenerally 3 seconds or more and 600 seconds or less, preferably 5seconds or more and 200 seconds or less, and more preferably 10 secondsor more and 60 seconds or less.

When a resin is molded by liquid injection molding (LIM molding), thecold resin is introduced into a hot mold and the viscosity risesaccompanying the chemical reaction, and as a consequence the resintypically reaches the mold unchanged with an inadequate viscosity rise.That is, a delay in the viscosity rise for the temperature conditions isproduced, and as a consequence the viscosity of the resin must becontrolled and the mold-to-mold precision and the precision of theclearances between the lead frame and mold must also be high. In thecase of an inadequate viscosity rise when the resin reaches the mold,the resin can leak out from the clearances in the mold and theclearances between the lead frame and mold and flashing is then easilyproduced. A mold clearance precision of generally not more than 10 μm,preferably not more than 5 μm, and more preferably not more than 3 μm isrequired. Preheating the lead frame prior to its introduction into themold also has the effect of inhibiting the generation of flash along theleads.

Moreover, the penetration of the material into narrow spaces can bepromoted and the generation of air voids within the molded product canbe prevented by placing the mold under a vacuum when the resin ismolded.

When the degree of curing is represented graphically as a function ofthe curing time in liquid injection molding (LIM molding), the graphpreferably ascends in an S-shape. Incomplete filling of the mold canoccur when the initial rise in the cure is too rapid. Controlling thecure rate of the material and adjusting the viscosity are very importantfor inhibiting flashing and preventing incomplete filling of the mold.Once the resin material has been filled into the mold, a faster cure isfavorable because this can shorten the molding cycle and improve thereleasability through cure shrinkage.

The time to cure completion is generally within 60 seconds, preferablywithin 30 seconds, and more preferably within 10 seconds. A post-curemay be implemented as necessary. The cure rate can be adjusted throughthe selection of the type of platinum catalyst, the amount of catalyst,the use of a cure rate controlling agent, and the degree of crosslinkingof the polyorganosiloxane, and also through molding conditions such asthe mold temperature, the filling rate, and the injection pressure.

Compression molding methods can be carried out using a compressionmolding machine. The molding temperature may be selected as appropriatein conformity to the material, but is generally 80° C. or more and 300°C. or less, preferably 100° C. or more and 250° C. or less, and morepreferably 120° C. or more and 200° C. or less. The molding time may beselected as appropriate in view of the cure rate of the material, but isgenerally 3 seconds or more and 1200 seconds or less, preferably 5seconds or more and 900 seconds or less, and more preferably 10 secondsor more and 600 seconds or less.

Transfer molding methods can be carried out using a transfer moldingmachine. The molding temperature may be selected as appropriate inconformity to the material, but is generally 80° C. or more and 300° C.or less, preferably 100° C. or more and 250° C. or less, and morepreferably 120° C. or more and 200° C. or less. The molding time may beselected as appropriate in view of the gelation rate or cure rate of thematerial, but is generally 3 seconds or more and 1200 seconds or less,preferably 5 seconds or more and 900 seconds or less, and morepreferably 10 seconds or more and 600 seconds or less.

A post-cure may optionally be carried out with any of the moldingmethods, and the post-cure temperature is 100° C. or more and 300° C. orless, preferably 150° C. or more and 250° C. or less, and morepreferably 170° C. or more and 200° C. or less. The post-cure time isgenerally 3 minutes or more and 24 hours or less, preferably 5 minutesor more and 10 hours or less, and more preferably 10 minutes or more and5 hours or less.

<3. The Semiconductor Light-Emitting Device Package and theSemiconductor Light-Emitting Device>

The molded resin of the present invention for a semiconductorlight-emitting device is generally used for a semiconductorlight-emitting device in which a semiconductor light-emitting element ismounted. The semiconductor light-emitting device is composed of, forexample, a semiconductor light-emitting element 1, a molded resin 2, abonding wire 3, an encapsulant 4, a lead frame 5, and so forth, as shownin FIG. 1. In this case, the insulating molded resin and theelectroconductive material, e.g., the lead frame 5, are referred to asthe package.

The semiconductor light-emitting element 1 can be, for example, anear-ultraviolet semiconductor light-emitting element that emits lightat a wavelength in the near-ultraviolet region, a violet semiconductorlight-emitting element that emits light at a wavelength in the violetregion, or a blue semiconductor light-emitting element that emits lightat a wavelength in the blue region, and emits light at a wavelength 350nm or more and 520 nm or less. While only one semiconductorlight-emitting element is mounted in FIG. 1, a plurality ofsemiconductor light-emitting elements may be positioned, as shown inFIG. 2, in a linear or planar configuration, vide infra. Area lightingcan be provided by positioning the semiconductor light-emitting elements1 in a planar configuration, and such an embodiment is preferred when itis desired to intensify the output.

The molded resin 2 that is a constituent of the package is molded incombination with the lead frame 5. There are no particular limitationson the shape of the package, and it may be a flat plane or cup-shaped.The entire molded resin 2 may be composed of the molded resin materialof the present invention, or a portion thereof may comprise the moldedresin material of the present invention. A mode in which the moldedresin constituting the reflector component 102 is molded from the moldedresin material of the present invention, as shown in FIG. 2 discussedbelow, is a specific example of the case in which a portion of themolded resin 2 is comprised of the molded resin material of the presentinvention.

The lead frame 5 is composed of an electroconductive metal and functionsto energize the semiconductor light-emitting element 1 by feeding powerfrom outside the semiconductor light-emitting device.

The bonding wire 3 functions to fix the semiconductor light-emittingelement 1 in the package. In addition, in those instances wherein thesemiconductor light-emitting element 1 is not in contact with the leadframe, which forms an electrode, the electroconductive bonding wire 3functions to feed power to the semiconductor light-emitting element 1.The bonding wire 3 is bonded to the lead frame 5 by compression bondingand the application of heat and ultrasonic vibration.

The molded resin 2, which comprises the molded resin material of thepresent invention, can make the exposed area of the lead frame 5 verysmall. The molded resin molded from the molded resin material of thepresent invention tends to have a reflectivity equal to or higher thanthat of the material of the lead frame (for example, silver), and as aconsequence a high package reflectivity can be maintained even when themolded resin presents a large exposed area. As a result, a semiconductorlight-emitting device with a structure different from that ofconventional packages can also be obtained by using a package comprisingthe material of the present invention for a molded resin. For example, asemiconductor light-emitting device 200 equipped with a conventionalpackage is shown in FIG. 3. The lead frame 204 has a large exposed areain the semiconductor light-emitting device shown in FIG. 3. Since thereflectivity of the molded resin 201 has been lower than that of thelead frame 204, it has been necessary, in order for the semiconductorlight-emitting device to realize a high luminance, to provide a largesurface area for a lead frame 204 that uses a high reflectivitymaterial. When the lead frame 204 has such a large exposed area, thelight emission efficiency may be reduced due to discoloration of thelead frame when the package is used installed in a light-emittingdevice. However, the decline in the light emission efficiency caused bythis discoloration of the lead frame can be stopped by having theexposed area of the lead frame 5 be small, as in FIG. 1.

The molded resin 2 that is a constituent of the package is mounted withthe semiconductor light-emitting element 1 and is sealed with aphosphor-admixed encapsulant 4. The encapsulant 4 is a mixture providedby mixing a phosphor into a binder resin; the phosphor converts theexcitation light from the semiconductor light-emitting element 1 andemits fluorescence at a different wavelength from the excitation light.In the present embodiment, the encapsulant also functions as thephosphor layer. The phosphor present in the encapsulant 4 is selected asappropriate in conformity to the wavelength of the excitation light fromthe semiconductor light-emitting element 1. When a blue light-emittingsemiconductor light-emitting element is used as the excitation lightsource for a white light-emitting semiconductor iight-emitting device(white LED), the white light can be produced by incorporating green andred phosphors in the phosphor layer. In the case of a violet-emittingsemiconductor light-emitting element, white light can be produced byincorporating blue and yellow phosphors in the phosphor layer or byincorporating blue, green, and red phosphors in the phosphor layer.

For the binder resin present in the encapsulant 4, an appropriateselection can generally be made from transparent resins known for use inencapsulants. Specific examples are epoxy resins, silicone resins,acrylic resins, polycarbonate resins, and so forth, wherein the use ofsilicone resins is preferred.

Another mode of the semiconductor light-emitting device of the presentinvention will be described in detail using FIG. 2.

The semiconductor light-emitting device 1C of this embodiment iscomposed of a window-equipped housing 101, a reflector component 102, alight source component 103, and a heat sink 104. This light sourcecomponent 103 is provided with a light-emitting component 105 on acircuit substrate, and a chip-on-board (COB) configuration may be usedin which the semiconductor light-emitting element is directly mounted onthe circuit substrate 106 or a configuration may be used in which thesemiconductor light-emitting device is surface mounted, as in FIG. 1.When the light source component 103 has the COB configuration, thesemiconductor light-emitting element may be sealed, without using aframe, by an encapsulant resin molded in a dome shape or flat plateshape. A single semiconductor light-emitting element or a plurality ofsemiconductor light-emitting elements may be mounted on the circuitsubstrate 106. The reflector component 102 and the heat sink 104 may beformed into a single body with the housing 101 or may each be separatetherefrom and can be used as required. Viewed from the perspective ofthermal radiation, the light source component 103, the housing 101, andthe heat sink 104 preferably have a single body structure or are ingapless contact intermediated by a high thermal conductivity sheet orgrease. For example, a known transparent resin or optical glass can beused for the window 107, and this window 107 may have a flat shape ormay have a curved surface.

In the case of a phosphor-based white LED, the phosphor component may bedisposed at the light source component 103 or may be disposed at thewindow 107. The disposition at the window 107 enables the phosphor to beplaced at a position that is separated from the light-emitting elementand thus offers the advantage of inhibiting deterioration of thephosphor, which is readily degraded by heat and light, and therebymaking it possible to obtain uniform, high luminance white light on along-term basis.

When a phosphor layer is disposed at the window 107, production can becarried out by a method in which the phosphor layer is, for example,screen printed, die coated, or spray coated on (not shown) a transparentwindow material. Since, in such a configuration, the semiconductorlight-emitting element and the phosphor layer are disposed with adistance opened therebetween, deterioration of the phosphor layer by thelight energy from the semiconductor light-emitting element can beprevented, while the output of the light-emitting device can also beimproved. The distance between the semiconductor light-emitting elementand the phosphor layer of the window 107 is preferably from 5 to 50 mm.In order to reduce self-reabsorption and reabsorption among theindividual RGB phosphors, the phosphor layer for FIG. 2 can be executedas a multilayer structure in which the phosphor for each color used isseparately coated or can be formed in a pattern such as stripes or dots.

The shape of each feature of the semiconductor light-emitting device 1Cis not limited to that shown in the figure, and the device may befabricated, for example, with a curved surface feature or as necessarywith an attached dimmer or circuit protection device.

The location where the molded resin according to the present invention(referred to below simply as the “optical member”) is deployed in thesemiconductor light-emitting device of the present invention asdescribed hereabove is not particularly limited to that alreadydescribed above. For example, it can be used for each of the followingmembers in the semiconductor light-emitting device 1C shown in FIG. 2;the housing 101, the reflector component 102, the light source component103, the light-emitting component 105, and the circuit substrate 106.The molded resin according to the present invention exhibits a highreflectivity for ultraviolet-to-visible light and an excellent heatresistance and light resistance, and in consequence thereof caninexpensively provide a highly durable high-luminance lighting device inwhich the required number of semiconductor light-emitting elements hasbeen brought down. In particular, through its high reflectivity forultraviolet-to-blue light, the molded resin of the present invention caneffectively reflect the light generated from the semiconductorlight-emitting element prior to wavelength conversion by the phosphorand is thus well adapted for embodiments in which the phosphor layer ispositioned at a location separated from the light source component. Whenthe emitted light color of the semiconductor light-emitting element isultraviolet to near-ultraviolet, the main component of the reflectivefiller is preferably alumina, while in the case of a blue emitted lightcolor the main component is preferably alumina and/or titania.

The following characteristics are exhibited by a preferred molded resinfor a semiconductor light-emitting device, said molded resin beingprovided by molding the material of the present invention for a moldedresin for a semiconductor light-emitting device.

<3-1. The Reflectivity of the Semiconductor Light-Emitting DevicePackage>

The semiconductor light-emitting device package of the present inventionis characterized by the ability to maintain a high reflectivity not onlyfor visible light, but also for ultraviolet light and near-ultravioletlight having a shorter wavelength than violet. The reflectivity forlight at a wavelength of 360, 400, and 460 nm is in each case generallyat least 60%, preferably at least 80%, and more preferably at least 90%.A semiconductor light-emitting device package provided with the moldedresin of the present invention, which exhibits a high reflectivity fromthe ultraviolet region to the visible region, has very goodcharacteristics not seen in prior semiconductor light-emitting devicepackages. Particularly for semiconductor light-emitting device packagesmade of a resin such as a polysiloxane, these are characteristics thatthe individual skilled in the art could not heretofore have easily hitupon and the technical significance is quite substantial.

<3-2. The Thickness of the Semiconductor Light-Emitting Device Package>

The semiconductor light-emitting device package of the present inventiongenerally has a chip-mounting surface and a back surface on the sideopposite from this chip-mounting surface. In such cases, the distancebetween this chip-mounting surface and the back surface, i.e., thethickness of the semiconductor light-emitting device package, isgenerally at least 100 μm and preferably at least 200 μm. It isgenerally not more than 3000 μm and preferably not more than 2000 μm.When the thickness is too small, problems can appear such as thepenetration of light to the back surface and a reduction in thereflectivity and an inadequate package strength resulting in deformationduring handling. When the thickness is too large, the package itself isalso thick and bulky, resulting in limitations on the uses andapplications of the semiconductor light-emitting device.

EXAMPLES

The present invention is described in additional detail with thefollowing examples, but the present invention is in no way limited bythese examples.

Example 1 Synthesis of Polyorganosiloxane (1)

A vinyl group-containing polydimethylsiloxane (vinyl group content: 1.2mmol/g, viscosity adjusted to 1000 mPa·s by the addition of finelydivided silica particles, contained 6.8 ppm of a platinum complexcatalyst) and a hydrosilyl group-containing polydimethylsiloxane (vinylgroup content: 0.3 mmol/g, hydrosilyl group content: 1.8 mmol/g,viscosity adjusted to 2100 mPa·s by the addition of finely dividedsilica particles) were mixed at 1:1 to obtain a liquid heat-curablepolyorganosiloxane (1) having a viscosity of 1500 mPa·s and a platinumconcentration of 3.4 ppm.

The finely divided silica particles corresponded to the fluiditycontrolling agent (E) and were added at a polyorganosiloxane: finelydivided silica particle (weight ratio) of from 80:20 to 89.5:10.5 toprovide the viscosities indicated above.

Synthesis of Polyorganosiloxane (2)

A vinyl group-containing polydimethylsiloxane (vinyl group content: 0.3mmol/g, viscosity: 3500 mPa·s, contained 8 ppm of a platinum complexcatalyst), a hydrosilyl group-containing polydimethylsiloxane (vinylgroup content: 0.1 mmol/g, hydrosilyl group content: 4.6 mmol/g,viscosity: 600 mPa·s), and a retarding component (cure rate controllingagent (D))-containing polydimethylsiloxane (vinyl group content: 0.2mmol/g, hydrosilyl group content: 0.1 mmol/g, alkynyl group content: 0.2mmol/g, 500 mPa·s) were mixed at 100:10:5 to obtain a liquidheat-curable polyorganosiloxane (2) having a platinum concentration of 7ppm.

The refractive index of this liquid heat-curable polyorganosiloxane (2)was 1.41.

[Preparation of the Material for a Molded Resin and Test PieceFabrication]

(A) The liquid heat-curable polyorganosiloxane (1) obtained as describedabove, (B) white pigment (refer to Table 1 below), and (E) fluiditycontrolling agent in the form of “AEROSIL RX200” (specific surface area:140 m²/g) finely divided silica particles were blended in the weightratio shown in Table 2 and the white pigment and finely divided silicaparticles were dispersed in (1) by stirring to obtain a white materialfor a molded resin. Using a hot press, these materials were cured for acure time of 240 seconds at 10 kg/cm² and 180° C. to obtain a circulartest piece with a diameter of 13 mm. The thickness of each test piece isgiven in Table 3.

[Measurement of the Primary Particle Diameter of the White Pigment andthe Aspect Ratio of the Primary Particles of the White Pigment]

The primary particle diameter of the white pigments (alumina powder)used in the examples was measured by SEM observation. When the particlediameter exhibited variation, several points (for example, 10 points)were subjected to SEM observation and the average value was then usedfor the particle diameter. In particular, when a large variationoccurred, for example, when the difference between the small particlediameter and the large particle diameter was greater than or equal toabout 5 times excluding coarse particles and microfine particles presentin trace amounts, the maximum value and minimum value were recorded. Inaddition, the length of the major axis (the largest long diameter) andthe length of the minor axis (the length of the longest part in thedirection perpendicular to the long diameter) were also measured, andthe length of the major axis was used for the primary particle diameterand the value obtained by dividing the length of the major axis (thelargest long diameter) by the length of the minor axis (the length ofthe longest part in the direction perpendicular to the long diameter)was used as the aspect ratio. The results are given in Table 1.

[Measurement of the Median Diameter D₅₀ of the Secondary Particles inthe White Pigment]

10 g of a 0.2% aqueous sodium polyphosphate solution was added to 10-20mg of the white pigment (alumina powder) and the alumina was dispersedby ultrasonic vibration. Using this dispersion, the volume-based mediandiameter D₅₀ of the secondary particles in the white pigment wasmeasured with a Microtrac MT3000II from Nikkiso Co., Ltd. The mediandiameter D₅₀ refers to the particle diameter at the point where thevolume based particle size distribution curve in cumulative % intersectswith the horizontal axis at 50%. The results are given in Table 1.

[Measurement of the Crystallite Size in the White Pigment]

The crystal system was determined by carrying out X-ray diffractionmeasurement on the alumina powder using an X'Pert Pro MPD fromPANalytical B.V. The (113) crystallite size was calculated for theα-alumina using the Scherrer equation.

Examples 2 to 9 and Comparative Examples 1 to 7

Test pieces with the thicknesses shown in Table 3 were obtained usingthe same conditions as in Example 1, but using the white pigment givenin Table 2 and preparing the blend of (A) liquid heat-curablepolyorganosiloxane (1) or (2), (B) white pigment, and “AEROSIL RX200”finely divided silica particles as the (E) fluidity controlling agentusing the weight ratio shown in Table 2.

The white pigments A to J in Table 2 are described in Table 1.

TABLE 1 median diameter 113 white primary particle of the secondaryaspect crystal crystallite pigment type shape diameter x (μm) particlesy (μm) y/x ratio system size (Å) purity A alumina crushed 0.3 1.2 4 1.48α 1020 99.1 B alumina crushed 0.2 to 1   1.4 1.4 to 7 1.63 α 1010 99.4 Calumina crushed 0.3 0.49 1.6 1.59 α  650 99.6 D alumina crushed 0.0140.4 28.6 — γ — >99.99 E alumina crushed 3 to 5 3.6 1 1.58 α 1260 99.9 Falumina spherical 0.1 to 0.8 0.46 1 1.08 non-α — >99.8 G aluminaspherical 3 3 1 1.04 non-α — >99.0 H alumina crushed 3.2 5.8 1.8 — α —99.5 I titania crushed 0.28 — — 1.45 rutile — 90 J titania crushed 0.03to 0.05 — — — rutile — 93 to 98 The titania designated as white pigmentI had a thin-film coating of silica and alumina on its surface. The “—”in the table indicates that the measurement was not performed.

TABLE 2 blending ratio: resin/white pigment/finely divided silicaparticles (the numerical value for the finely divided silica particlesexcludes the finely divided silica white fluidity particles resin pig-controlling present in the (polyorganosiloxane) ment agent resin)Example 1 (1) C finely 40/60/0 divided silica particles Example 2 (1) Afinely 40/60/0 divided silica particles Example 3 (1) A finely 35/60/5divided silica particles Example 4 (1) B finely 40/60/0 divided silicaparticles Example 5 (1) B finely 25/70/5 divided silica particlesExample 6 (2) A finely 30.6/52/4.4 divided (also include silica 13 forthe particles + spherical spherical silica) silica with a particlediameter of 4 μm Example 7 (2) A finely 56.9/35/8.1 divided silicaparticles Example 8 (2) I 0 40/60/0 Example 9 (2) A, I 0 40/60(A:I =48:12)/0 Comp. (1) F finely 40/60/0 Example 1 divided silica particlesComp. (1) G finely 40/60/0 Example 2 divided silica particles Comp. (1)D finely 51/49/0 Example 3 divided silica particles Comp. (1) E finely40/60/0 Example 4 divided silica particles Comp. (2) H finely 35/60/5Example 5 divided silica particles Comp. (2) H 0 20/80/0 Example 6 Comp.(2) J 0 40/60/0 Example 7

In the case of the material in Comparative Example 3, which used analumina with a primary particle diameter less than 0.1 μm, the viscositywas raised to the point that the difficulty of dispersing the whitepigment made possible only a 49% alumina loading.

[Reflectivity Measurements on the Test Pieces]

Using a SPECTROPHOTOMETER CM-2600d from Konica Minolta, the reflectivityat wavelengths from 360 nm to 740 nm was measured on a 6 mm measurementdiameter on each of the test pieces in Examples 1 to 9 and ComparativeExamples 1 to 1. The results are shown in Table 3 and FIG. 4. Thereflectivity was also measured on very thin test pieces in Examples 2and 9 and Comparative Example 5.

TABLE 3 reflectivity reflectivity for 400 nm for 460 nm test piece lightlight thickness (μm) Example 1 94.6 94.9 400 Example 2 94.4 94.8 420Example 3 95.1 95.1 410 Example 4 92.4 92.5 360 Example 5 93.7 93.8 370Example 6 94.1 93.8 340 Example 7 93.0 92.6 420 Example 8 40.6 97.5 320Example 9 44.6 97.1 290 Comparative 89.0 92.2 360 Example 1 Comparative82.2 84.5 520 Example 2 Comparative 74.0 71.4 1000 Example 3 Comparative85.4 86.0 370 Example 4 Comparative 86.5 87.4 520 Example 5 Comparative87.4 88.3 470 Example 6 Comparative 41.4 91.6 370 Example 7 Example 288.0 86.9 120 Example 9 44.6 95.2 120 Comparative 70.9 70.3 120 Example5

According to Table 3, a very high reflectivity at 460 nm wasdemonstrated in Examples 1 to 9, which used a nonspherical white pigmentthat had the prescribed values for the primary particle diameter andaspect ratio. In addition, Table 3 also shows that when the whitepigment was alumina a high reflectivity was maintained over a broadrange from the ultraviolet region to the visible light region. On theother hand, it was shown that the reflectivity at 460 nm was somewhatreduced in Comparative Examples 1 and 2, which used a spherical whitepigment. Moreover, even when the white pigment was alumina, the extentof the decline was shown to be substantial for the reflectivity at 400nm. The reflectivity was low in Comparative Examples 3 and 7, which usedalumina with a primary particle diameter below 0.1 μm, and inComparative Examples 4, 5, and 6, which used alumina with a primaryparticle diameter above 2 μm.

In the case of the 120 μm-thick test pieces, Examples 2 and 9 had ahigher reflectivity for 460 nm light than did Comparative Example 5 andmaintained a relatively high reflectivity even for the thin material. Inparticular, it was found that little decline in reflectivity occurredfor the thin test piece in Example 9, which had titania blended in thealumina.

[Measurement of the Viscosity of the Material for a Molded Resin]

Using an RMS-800 from Rheometrics, Inc., with parallel plate, theviscosity was measured at a measurement temperature of 25° C. on each ofthe materials for a molded resin of Examples 1 to 7 and ComparativeExamples 2, 4, 5, and 6.

The results are shown in Table 4 and FIG. 6. It is demonstrated herethat, for all the materials in Examples 1 to 7, the viscosity at 25° C.and a shear rate of 1 s⁻¹, the viscosity at 25° C. and a shear rate of100 s⁻¹, and their trends are entirely suitable for molding a moldedresin. On the other hand, the viscosity values in the comparativeexamples are shown to be substantially different from those in theexamples. The viscosity in Comparative Example 6 was so high thatslippage occurred between the parallel plates and the sample andaccurate measurements could not be taken.

TABLE 4 viscosity viscosity (1 s⁻¹) viscosity (100 s⁻¹) ratio (Pa · s)(Pa · s) (1 s⁻¹/100 s⁻¹) Example 1 1617.1 30.3 53.4 Example 2 4859.541.9 116.0 Example 3 24290.2 701.5 34.6 Example 4 1099.6 26.1 42.2Example 5 80644.9 1827.3 44.1 Example 6 19506.1 198.3 98.4 Example 7641.9 56.5 11.4 Comparative 27.2 4.8 5.7 Example 2 Comparative 35.6 7.15.0 Example 4 Comparative 334.0 88.6 3.8 Example 5 Comparativemeasurement not measurement not measurement Example 6 possible possiblenot possible

Example 10

A package for a semiconductor light-emitting device was molded by liquidinjection molding using the material of Example 3 in combination with acopper lead frame that had been silver plated over its entire surface.This package was a cup-shaped surface-mount package with the resinportion having length 3.2 mm×width 2.7 mm×height 1.4 mm and a concaveportion with a diameter of 2.4 mm for the opening. Molding was performedfor a curing time of 20 seconds at a mold temperature of 170° C.Observation of the molded package showed the package to be free of flashand free of short molding.

Example 11

A package for a semiconductor light-emitting device was molded by liquidinjection molding using the material of Example 3 in combination with acopper lead frame that had been silver plated over its entire surface.This package was a cup-shaped surface-mount package having length 5mm×width 5 mm×height 1.5 mm and a concave portion with a diameter of 3.6mm for the opening. Molding was performed for a curing time of 180seconds with a 150° C. mold. The molded package was sectioned with amicrotome while frozen with liquid nitrogen and the package crosssection was observed by SEM. The primary particle diameter of thealumina exposed in the cross section was 0.3 μm and the primary particleaspect ratio was 1.42.

EXPLANATION OF REFERENCE NUMERALS

-   1 semiconductor light-emitting element-   2 molded resin-   3 bonding wire-   4 encapsulant-   5 lead frame-   1C semiconductor light-emitting device-   101 housing-   102 reflector component-   103 light source component-   104 heat sink-   105 light-emitting component-   106 circuit substrate-   107 window-   200 conventional semiconductor light-emitting device-   201 molded resin-   202 semiconductor light-emitting element-   203 encapsulant-   204 lead frame

1. A material for a molded resin for a semiconductor light-emittingdevice, the material comprising (A) a polyorganosiloxane, (B) a whitepigment, and (C) a curing catalyst, wherein the white pigment (B) hasthe following characteristics (a) and (b): (a) a primary particle aspectratio is 1.2 or more and 4.0 or less, and (b) a primary particlediameter is 0.1 μm or more and 2.0 μm or less.
 2. The material for amolded resin according to claim 1, wherein a median diameter ofsecondary particles of the white pigment (B) is 0.2 μm or more and 5 μmor less.
 3. The material for a molded resin according to claim 1,wherein a viscosity at a shear rate of 100 s⁻¹ and at 25° C. is 10 Pa·sor more and 10,000 Pa·s or less.
 4. The material for a molded resinaccording to claim 3, wherein a ratio of a viscosity at a shear rate of1 s⁻¹ to a viscosity at a shear rate of 100 s⁻¹ is at least
 15. 5. Thematerial for a molded resin according to claim 1, wherein the whitepigment (B) is alumina.
 6. The material for a molded resin according toclaim 1, wherein the ratio y/x of the median diameter y of the secondaryparticles in the white pigment (B) to the primary particle diameter x inthe white pigment (B) is 1, or more and 10 or less.
 7. The material fora molded resin according to claim 1, wherein the polyorganosiloxane (A)is a thermosetting polyorganosiloxane that is a liquid at normaltemperature and normal pressure.
 8. The material for a molded resinaccording to claim 1, further containing (D) a cure rate controllingagent.
 9. The material for a molded resin according to claim 1, furthercontaining (E) a fluidity controlling agent.
 10. The material for amolded resin according to claim 9, wherein a total content of the whitepigment (B) and the fluidity controlling agent (E) is at least 50 weight% with regard to the entire material for a molded resin.
 11. A moldedresin for a semiconductor light-emitting device, that is obtained bymolding the material for a molded resin according to claim
 1. 12. Themolded resin according to claim 11, wherein a light reflectivity at athickness of 0.4 mm and a wavelength of 400 nm is at least 60%.
 13. Themolded resin according to claim 11, wherein the molded resin is moldedby liquid injection molding.
 14. A method of producing a molded resin,comprising: a step of producing the material for a molded resinaccording to claim 1; and a step of molding the obtained material for amolded resin by injection molding.
 15. A semiconductor light-emittingdevice that has the molded resin according to claim
 11. 16. A materialfor a molded resin for a semiconductor light-emitting device, thematerial comprising (A) a polyorganosiloxane, (B) a white pigment, and(C) a curing catalyst, wherein a viscosity at a shear rate of 100 s⁻¹and at 25° C. is 10 Pa·s or more and 10,000 Pa·s or less and a ratio ofa viscosity at a shear rate of 1 s⁻¹ to a viscosity at a shear rate of100 s⁻¹ is least 15.